specimens

I know you’re thinking “hasn’t she already covered tea?” and yes you’re correct. I have. However, Camellia sinensis (and all of the wonderful varieties of said species) is not the only plant that tea can be made from. In a more recent blog post you have seen that tea can be made from winter green (Gaultheria procumbens) and the same can be said for a lot of plants. Today I will be venturing into the world of Chrysanthemums – Chrysanthemum indicum and Chrysanthemum morifolium to be exact.

C. indicum is a perennial that grows to roughly 100cm tall and is native to China. Chrysanthemum originates from the greek “chryos” and “anthos” translating to golden flower. C. indicum lives up to the name and typically produces a beautiful array of small yellow flowers that flower from August through to October however a multitude of colours are available amongst varieties. One particular variety, C.indicum var. edule (Kitam), is grown and cultivated as a vegetable in China. C. indicum is also one of the main parents of C. morifolium. C. morifolium is less cold hardy than its parental species, often requiring to be stored in greenhouses in Britain when during the cooler weather. However C.morifolium is far larger than its parental species and so is often favoured as a garden ornamental plant. In 1630 over 500 cultivars were listed and in the centuries since numbers have continued to rise generating plants that range from 30 – 120cm tall, with large blooms again in a range of colours.

Chrysanthemum indicum

Aside from being beautiful garden plants Chrysanthemums have also been used in Chinese medicine dating back to 475 -221 BCE and the production of tea. The leaves from both species can be used to brew tea, with cultivars of C. morifolium developed so that leaves are less bitter. The flowers, specifically the petals, of C. morifolium can also be brewed to produce a delicately sweet flavoured tea that is also very beautiful to look at. The tea itself is said to help improve vision by soothing sore eyes and headaches as well as reducing infection and inflammation. Chrysanthemums are said to have antibacterial, antifungal and anti-inflammatory properties and so flowers would often be collected in Autumn and dried so that they could be used later as an infusion. Chrysanthemum tea is also recommended as an alternative to tea from Camellia sinensis for reducing blood pressure.

Flower heads and leaves can also be used in a variety of dishes. Leaves can be battered and turned into fritters and the petals can be pickled or served with soy sauce alongside tofu and salad. Why not try some Chrysanthemum tea or a sprinkling of petals in your salad next time you’re out in the garden?

As always, let me know in the poll below what you would like to see next and stay tuned for the next Travelling Botanists blog post.

I’m taking a break from my travels to celebrate world soil day. World soil day celebrates the importance of soil in our natural environment and contributes enormously to human well-being through providing a place to grow crops and supporting all walks of life.

In many parts of the world soil is now contaminated with heavy metals and radioactive elements as a by product of mining and various other human activities. This renders the soil unusable and unsuitable for feeding livestock, growing crops and restoring natural habitats. However there are many plants, known as hyperaccumulators, that are able to absorb these heavy metals through their roots, often concentrating them in their leaves. This process is known as phytoremediation. These metals can be retrieved from the plants by burning them, a process known as phytomining. By using natural hyperaccumulators we can reclaim those areas affected by mining and hopefully restore some natural habitats in the process.

I’ll soon be crossing the border into Southeast Asia and exploring the many wonderful plants there but there’s time for one last post!

Oryza sativa

Oryza sativa, which translates to “rice” and “cultivated”,remains a staple for half of the worlds population. It is a widely cultivated plant, growing in over 100 countries and on all continents with exception of Antarctica. There are currently 40,000 varieties of rice of which over 100 of these are grown globally. Oryza rufipogon grows through South and Southeast Asia, it is the wild relative of Oryza sativa. The earliest recorded cultivation of rice has been documented to be in China around 6000 BC.

Within the species sativa, two subspecies have been classified: japonica, indica. Japonica varieties are short-grained and sticky, often grown in higher altitudes such as the uplands of Southeast Asia. Indica on the other hand are long-grained and non-sticky varieties grown in the lowlands and often submerged. Javanica, now known as tropical japonica, is a subgroup to japonica and is made up of broad-grained varieties grown in tropical conditions. However classification of rice has changed numerous times due to differing basis of classification such as the types of enzymes present or short sequence repeats in the DNA.

Oryza sativa can grow either 1M tall in dry conditions or 5M long in submerged conditions. The stem is composed of several nodes and from each node grows a long, slender leaf. The seeds, like other grass species, grow on long spikes which have the tendency to arch over with the weight of the seed. It is the endosperm of these seeds which we consume. Whilst rice can be found in many colours such as white, brown, red, purple and black we commonly eat either the white or brown rice. White rice is typically polished (milled) to remove the bran layer, where as wholegrain “brown” rice has the bran layer intact. The bran layer, present in all cereal crops, is rich in essential amino acids, dietary fibre and antioxidants.

Oryza sativa field

96% of the rice that is grown worldwide is consumed by the same countries that grow it however these countries also suffer from Vitamin A deficiency. Scientists have tried to improve the nutritional quality of rice by introducing enzymes from other plants via genetic modification that are needed to synthesise beta-carotene. Beta-carotene is converted into Vitamin A in the intestines. The Golden Rice Project aims to reduce the incidence of Vitamin A deficiency (VAD) syndrome which is prevalent in these countries.

Generally rice is steamed or boiled however it can also be used to produce several other products. Rice can be pressed in order to produce rice milk, which is an excellent alternative for those avoiding dairy products who may also have a nut allergy however it is rich in carbohydrates and low in protein and so is not necessarily the best option for diabetics or the elderly. In Japan, sake is made from brewing milled rice somewhat similar to beer however the conversion of starch to sugar and then sugar to alcohol occurs simultaneously. Sake is customarily sipped from a small cup known as a sakazuki on special occasions.

Rice is also used in many traditional medicines such as Ayurveda such as in the treatment of diarrhea. Rice would be boiled and then strained, allowing the water to cool. The patient would then drink the rice water which would stop the diarrhoea or ease the stomach upset as well as re-hydrating them. Congee is a traditional dish made using a single grain, often brown rice, and slowly cooking it on low heat with a 1:5 or 1:6 ratio of rice to water. Congee is said to be very beneficial to those with low energy and issues regarding weight loss/gain and is made across India and China. Several studies such those using rice callus and extracts have shown that rice also has anticancer properties by inhibiting growth of human cancer cells.

If you have any suggestions for the types of plants you wish to learn about please fill in the poll below or if you have any specific queries please leave a comment.

2016 marks the international year of the pulses, decided back in 2013 at the 68th session of the United Nations General Assembly. The Food and Agriculture Organization nominated pulses in the hope that this would raise awareness of their importance in providing a sustainable source of plant protein.

Throughout the the year there have been many conferences, discussions and workshops held in order to promote a better understanding and public awareness on topics surrounding sustainable food production, food security and nutrition as well as improvements in crop rotation and how we can work towards improving trade connections of pulses and utilization of plant based proteins. Whilst none of these events are taking place in the UK many resources are available online at their website including recipes and videos for you to watch.

As with all my other blog posts I have found some specimens within our collection to show you.

The Chick Pea (Cicer arietinum)

Cicer arietinum

“This interesting little leguminous plant has been an object of cultivation from time immemorial & grows wild at the present day in the cornfields”

C. arietinum is one of the earliest cultivated legumes dating back around 7,500 years ago in the Middle East. Production is rapidly increasing across Asia as superior cultivars are developed and released. Many country farmers depend upon this legume for a source of income however legumes also enrich the soil through the addition of nitrogen.

This small plant, reaching heights of 20-50 cm, may not look like much but the seeds pack a punch. Approximately 100g of these seeds provides ~20% of protein, dietary fibre and other minerals needed, thereby providing a cheaper alternative to those who cannot afford meat or choose not to eat it. Leaves are also consumed providing essential micro-nutrients which are significantly higher than in cabbage and spinach.

A study has also shown that the chickpea can also be used as an animal feed, with many groups of animals benefiting.

The Pigeon Pea (Cajanus cajan)

Cajanus cajan

The pigeon pea often grows between 1-4M tall with a tap root reaching around 2M. This legume is also a major source of protein for those living in South Asia and has been consumed across Asia, Africa and Latin America since it was first domesticated in India around 3,500 years ago.

It is a perennial plant that is harvested for between 3-5 years however after the second year the yield drops and so annuals are more often used as a means to harvest the seed. Like the chickpea, the pigeon pea is also able to enrich soils with nitrogen and its leaves are often used to feed cattle whilst the woody stem is used for firewood.

Black Lentil (Vigna mungo aka Phaseolus mungo L.)

Vigna mungo

Vigna mungo can be found in various forms ranging from a fully erect plant to one that trails growing between 30-100cm. It produces large leaves which are hairy and seed pods that are approximately 6cm long.

It is very popular in India where the seed is split and made into dal. The Black Lentil is very nutritionally rich containing 25g of protein per 100g of seed as well as many other important micro-nutrients and therefore plays a huge role in the diets of those from India.

Whilst volunteering at the herbarium I came across several small boxes containing bewitchingly bright red seeds and an equally garish TOXIC sign. They were labelled Abrus precatorius seeds, and that one of their common names is the rosary pea suggests that I am not the first to be taken in by their beauty. The seeds of Abrus precatorius have the eye-catching red of hawthorn berries capped with a black spot at the hilum, but glossy and sturdy enough to be drilled to make beads for jewellery.

The contrast between the beauty of the seeds and their toxicity inspired us to begin a blog series on toxic plants called The Poison Chronicles. We want to look at how they can kill, but also why they have evolved this ability and if the plant has any other products that are medicinally useful.

Abrus precatorius is a vine in the Legume family native to the Old World Tropics, but was introduced to the Neotropics for it’s ornamental value, but is now an invasive species. It proliferates after a forest fire so can out-compete slower growing plants, it’s suckering ability makes it difficult to remove.

But these seeds are more than just beautiful. They have earned their TOXIC label as they contain the toxin abrin, which has a very low fatal dose, reported in the literature as around 0.1 – 1μg/kg, making it one of the most toxic known plant products. Abrin acts by inhibiting protein synthesis, so can affect all cells in the body. A few hours after a person has ingested a lethal dose of abrin, they may experience severe vomiting, gastrointestinal bleeding, dehydration, multi-organ damage and death often within 36-72 hours. The incredible toxicity of abrin was occasionally used to secretly kill people in 19th century Bengal. The seeds were ground into a paste, shaping into a point known as a sui and left to harden in the sun. This was then mounted on a handle and stuck through the person’s skin by a surreptitious slap to the cheek.

Abrus precatorius seeds

Despite this toxic plant being widespread, there have been very few cases of abrin poisoning. The thick indigestible coat of mature seeds meaning that if seeds are swallowed whole, they are unlikely to release much abrin and symptoms are mild. Chewing the seed releases the toxin, and it has been reported that a single well chewed seed could kill. However, a case of a patient attempting suicide through ingesting 10 crushed A. precatorius seeds survived after swallowing activated charcoal. Except when used or taken deliberately, it is surprisingly difficult for humans to be poisoned by A. precatorius, so for most this plant poses more of a threat to your garden as an invasive than your health.

An obvious question is why these seeds contain such a deadly toxin. I have been unable to find any research on this. But it may be that the thick seed coat means the toxin isn’t a defence against herbivores ingesting the seeds at all. As it has been reported that the seed is dispersed by birds who would not chew the seed and would instead disperse them in faeces, it is possible it is a defence against mammals chewing the seeds.

A. precatorius has not always been seen as a deadly beauty, and has been used a traditional medicine. Extracts of the seeds have been used in the Pothohar region of Pakistan as a purgative and an aphrodisiac and in rural Bangladesh to treat erectile dysfunction. The symptoms of poisoning by abrin suggests very low doses could work as a purgative, there is a high risk of administering a lethally high dose.

A. precatorius‘ entire biochemical system makes it toxic, so single chemical plucked out of this network can have very different properties from the plant as a whole. In contrast its traditional uses, experiments have been done which show that abrin injected into laboratory mice damages the DNA and reduces production of sperm cells, though the long time period needed for DNA repair to occur means it is unlikely to be used in commercial birth control.

Abrus precatorius demonstrates the multi-faceted nature of plants: at once a beauty and a (potential) killer; a toxin and used as a medicine.

We hope you have enjoyed our first installment of The Poison Chronicles. You can find more information following the link below